The Making of Species 
protoplasm a growth-force, which makes each 
organism in itself a force making towards pro- 
gressive evolution. He holds that animals and 
plants would have become much as they are now 
even if no struggle for existence had taken place. 
“To the believers in this kind of . . . ortho- 
genesis,” writes Kellog (Darwinism To-day, p. 
278), “organic evolution has been, and is now, 
ruled by unknown inner forces inherent in organ- 
isms, and has been independent of the influence 
of the outer world. The lines of evolution are 
immanent, unchangeable, and ever slowly stretch 
toward some ideal goal.” It is easy to enunciate 
such a theory, impossible to prove it, and difficult 
to disprove it. 
It seems to us that the fact that, so soon as 
organisms are removed from the struggle for 
existence, they tend to degenerate, is a sufficient 
reason for refusing to accept theories of the 
description put forth by Naegeli. More truly 
Lamarckian is Eimer’s theory of orthogenesis, 
according to which it is the environment which 
determines the direction which variation takes ; 
and the variations which are induced by the 
environment are transmitted to the offspring. 
Spencer and Orr preach nearly pure Lamarck- 
ism. The former, while fully recognising the 
importance of natural selection, considered that 
sufficient weight has not been given to the 
effects of use and disuse, or to the direct action 
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